Most natural gas consumed in the United States is not produced in the areas where it is most needed. To transport gas from increasingly remote production sites to consumers, pipeline companies operate and maintain hundreds of thousands of miles of natural gas transmission lines. This gas is then sold to local distribution companies, who deliver gas to consumers using a network of more than a million miles of local distribution lines. This vast underground transmission and distribution system is capable of moving many billions of cubic feet of gas each day. To provide force to move the gas, operators install large compressors at transport stations along the pipelines.
Reciprocating gas compressors are a type of compressor that compresses gas by using a piston in a cylinder and a back-and-forth motion. A suction valve in the cylinder receives input gas, which is compressed, and discharged through a discharge valve. Reciprocating compressors inherently generate transient pulsating flows and various devices and control methods have been developed to control these pulsations. A proper pulsation control design reduces system pulsations to acceptable levels without compromising compressor performance.
A common method for pulsation control is the use of “filter bottles”, also called “pulsation filters”, placed between the compressor and the pipeline headers. These filters operate with surge volumes and are implemented as volume-choke-volume devices. They function as low-pass acoustic filters, and attenuate pulsations on the basis of a predetermined Helmholtz response.